1. Field of the Invention
The present invention relates generally to spectrometers and, more particularly to an apparatus for the rapid determination of metals in the outdoors.
2. The Prior Arts
Apparatus for the spectrometric analysis of the chemical composition of substances, such as metallic parts, have been known for some time. In a known apparatus of this type, two or three spacing supports are located adjacent a vaporizing device, formed as a spark electrode, and holding the spark electrode at a definite distance from the substance when positioned on the substance. The radiation emitted by the metal vapor brought to luminescence by the device is transferred to a spectroscope by a flexible optical waveguide. The waveguide is fastened to the base of a probe and its free end constitutes the sensing head and is pointed towards the plasma of the luminous metal vapor. The spectroscope is housed in a mobile unit, which also contains the energy source for the vaporizing device (German Pat. No. 2,626,233).
It has been learned that external factors affect the operation and the range of application of such an apparatus. Specifically, factors which impair the stability of a plasma, such as the stability of a spark or of an arc, and factors which affect the transmission of the radiation from the luminous metal vapor to the sensing head. Thus, the stability of the spark is impaired by uncontrollable air currents which can not be completely eliminated by the location of the spark electrode in a chamber alone. The transmission of the radiation is attenuated when passing through air. The attenuation depends on the wavelength of the light and increases as the wavelength becomes shorter. This known manually-operated apparatus is accordingly suitable only for the determination of components with long wavelengths. The analytical determination of components which produce radiation of short wavelengths must, therefore, be accomplished in a laboratory with stationary equipment, now as in the past. In the laboratory, a sample of the part to be analyzed is studied in a protective gas atmosphere, such as an argon atmosphere, whereby wavelengths below 250 nm can also be determined.
Another disadvantage of this known equipment resides in that that part of the vaporized material itself settles on the sensing head which weakens the transmitted radiation. The apparatus, therefore, must be cleaned from time to time.
Besides apparatus of this kind, equipment is known in which the spectrometric analytical apparatus is accommodated in a portable cabinet, housing the vaporizing device. A sleevelike chamber, open on one end, surrounds the device and serves as a spacing support. This apparatus is unwieldy and requires great physical effort for handling by an operator (German Pat. Nos. 2,513,345 and 2,513,358).
A device is also known in which an opening is provided in the rear of the electrode chamber through which gases formed are allowed to escape (British Pat. No. 1,444,255).